Talking about the main points of battery installation in off-grid power generation system
acceptance
1) Appearance inspection should be carried out in time after the storage battery arrives, because the appearance defect will often affect the internal quality of the product.
2) According to the time when the battery leaves the factory, determine whether supplementary power is needed, and perform terminal voltage inspection, capacity test, and internal resistance test. If the battery is only visually inspected after delivery, and stored without supplementing the battery’s delivery time, the storage time at room temperature exceeds six months (temperature>33°C is three months), its technical performance indicators will definitely decrease. It can't even be used.
Install
The quality of battery installation directly affects the reliability of battery operation, so the installation personnel must be trained or trained personnel to complete the battery installation work.
When the battery is being transported, do not lift the pole to avoid damage to the battery. If the battery pole seal leaks, it will cause the battery connector to corrode and directly affect the battery's service life. Before installing the battery connector, the battery cells must be neatly arranged, and no lubricant or other chemicals must be used to avoid corroding the battery shell, causing the shell to rupture and electrolyte leakage. The technical conditions for battery installation are as follows:
1) Before installing the battery, check the battery shell to ensure that there is no physical damage. For suspicious spots that are wet, use a multimeter to connect one end of the battery to the battery terminal and the other end to a wet place. If the voltage is zero volts, the case is not damaged. If the voltage is greater than zero volts, it means there is acid in the place, and you need to check it carefully.
2) The battery should be installed in a clean, cool, ventilated and dry place as much as possible and avoid direct sunlight. Keep away from heaters or other radiant heat sources. In the specific installation, the installation method should be selected according to the plate structure of the battery, and it should not be tilted. Ventilation measures should be provided in the storage battery room to avoid explosion and combustion caused by the combustible gas produced by the storage battery. Since the battery generates heat during charging and discharging, the distance between the battery and the battery is generally greater than 50mm to allow the battery to dissipate heat well. At the same time, the connection between the batteries should meet the requirements of the discharge current. For the connection of the battery packs in parallel, the impedance should be equal. Do not use too thin or too long cables for the connection of the battery, the charging device and the load, so as to avoid the current conduction process on the line Excessive voltage drop and heat generation due to power loss are hidden dangers for safe operation.
3) Before the battery is installed, the time interval between battery production and installation and use should be verified. Measure the open circuit voltage of the batteries one by one. The batteries should generally be put into use within 3 months. If the battery is left for a long time, the open circuit voltage will be very low. At this time, the battery cannot be directly put into use. It should be recharged before use.
After installation, the voltage of the battery pack should be measured, and the DC gear of the digital meter should be used to measure the battery pack voltage. Vtotal is greater than or equal to N×12 (V) (N: the number of batteries in series, relative to 12V batteries); if Vtotal is less than N×12 ( V) Check the batteries one by one; if the battery group is connected in parallel after two groups of batteries are connected in series, the voltage of the two groups should be measured before connection, that is, Vtotal 1 is greater than or equal to N×12 (V); Vtotal 2 is greater than or equal to N×12 (V) (N: the number of batteries connected in series in parallel branches), the voltage error of the two battery groups should be within the allowable range.
4) The battery pack cannot be combined with old and new batteries. Instead, new batteries should be used or all old batteries that were originally the same group should be used to avoid imbalance between the working conditions of the new and old batteries, which would affect the service life and efficiency of all batteries. For batteries of different capacities, they must not be used in series in the same group. Otherwise, when discharging or charging with high current, there will be unsafe hidden dangers.
5) Before installing the battery, clean the battery terminal post to remove the oxide layer on the surface of the terminal post. The terminal post of the battery will form an oxide film in the air. Therefore, it is necessary to use a copper wire brush to clean the connection surface of the terminal post before installation. To reduce contact resistance.
6) A circuit breaker should be provided in the battery circuit group connected in series for maintenance; a parallel group should also be equipped with a circuit breaker for each group to facilitate future maintenance and replacement operations.
7) Make the connection between the positive and negative busbars of the battery pack and the busbars of the single battery firm and reliable.
For newly installed battery packs, a check discharge test should be carried out. After that, a check discharge test shall be carried out every 2 to 3 years, and a check discharge test shall be carried out once a year for batteries that have been in operation for 6 years. If the battery pack capacity does not reach more than 80% of the rated capacity after three check discharges, it can be considered that the battery pack has reached the end of its life and should be replaced.
Check after installation
The inspection items after installation include: installation quality, capacity test, internal resistance test and related technical data, etc. These aspects will directly affect the future operation and maintenance of the battery.
When testing, it is first necessary to have a comprehensive understanding of the principle, structure, characteristics and technical indicators of the battery under test. In order to safely and accurately complete the inspection work after the battery is installed, the user can choose the most suitable battery test instrument for inspection, testing and comparison according to their own existing equipment and technical conditions. The main test items are:
1) Capacity test. The capacity test is to discharge the current of the battery under test to the load for a specified time (Amp-hour) to determine its capacity to determine the position of the battery in the life cycle. This is the most ideal method. The newly installed battery must have the capacity Testing as part of acceptance testing.
2) Power-down test. Use the actual online load to test the battery. Through the test results, an objective and accurate battery capacity and high-current discharge characteristics can be calculated. When testing, try to be close to or meet the discharge current and time requirements as much as possible.
3) Measure the ohmic resistance inside the battery. Internal resistance is the best indicator of battery status. Although the method of testing battery internal resistance is not as absolute as load test, at least 80% to 90% of the batteries with problems can be detected by measuring internal resistance.
